Can't use gpt labels re-importing pool

[Tom Evans]

On Thu, Nov 26, 2009 at 8:50 AM, Jeremy Chadwick
<freebsd at jdc.parodius.com>wrote:

> I'm a bit curious about something, so maybe someone can help me
> understand:
>
> Why are people bothering with GPT labels (or in some cases, glabels)
> when AHCI (whether it be ataahci.ko or ahci.ko) is in use?  Under what
> circumstance would the device name change dynamically in this situation?
>
> I've never witnessed this happening with AHCI, at least on Intel
> systems, and I've hot-swapped hard disks many times over.
>
>
My home server has 6 x ICH10 SATA ports using ahci(4), and 2 x SiL 3128 SATA
ports using siis(4). When I first set it up, I created a raidz pool using
MBR/BSD slices/partitions on the drives on the ahci controllers, (ie zpool
create tank raidz ada[0-5]s1d). I then shutdown, connected a couple of
drives to the siis controller, and booted up again. This caused the pool to
fail to be imported, as the drives on siis came up as ada0 and ada1.

I then wiped out the pool, and restarted the install, but this time using
GPT partitioning and labelling each partition that I use. Now I can connect
my drives on any interface, any order and it works correctly, always. I also
get a nice label for each drive that I can scribble on the drive cage, and I
can tell exactly what physical device is referred to by a label.

The only cost to this was having to remember to label the drives - well
worth it imo.

Cheers

Tom